Comment period extended for plan to cull 16,000 cormorants from Columbia estuary

The U.S. Army Corps of Engineers this week announced it has extended by 15 days the public comment period on a draft plan detailing possible alternatives to reduce predation by double-crested cormorants on juvenile salmon and steelhead that are listed under the Endangered Species Act.

A large number cormorants nests each spring and summer in the Columbia River estuary. Their primary colony site is East Sand Island, which millions of listed salmonids must pass on their way to the Pacific Ocean.

The Corps’ draft Environmental Impact Statement on the predation plan was released for public comment June 12.

Among the proposed management alternatives considered in the draft is the implementation of non-lethal and lethal actions to reduce the colony size on East Sand Island and limit their dispersal within the Columbia River estuary.

Non-lethal methods considered include various hazing techniques to reduce colony size and conducting hazing activities off East Sand Island if new colonies establish throughout the Columbia River estuary.

Lethal methods considered include take of eggs and shooting individual double-crested cormorants.

The Corps’ “preferred” alternative involves the culling of individuals to achieve target colony size of about 5,600 breeding pairs. Culling would occur over four years, with the ability to achieve the target size in a shorter duration (3 or 2 years) under Adaptive Management,” the draft EIS says.

“Under the 4-year strategy, 20.3 percent of the colony would be culled per year. In total, 15,955 double-crested cormorants would be taken in all years (5,230, 4,270, 3,533, and 2,923 double-crested cormorants in years 1 to 4, respectively). The Corps would submit an annual depredation permit application to the USFWS for the proposed individual take levels and associated nest loss from take of those individuals,” the plan says.

Take would occur on- and off-island within the foraging range (25km) of the East Sand Island colony. Concurrent with culling, hazing supported with limited egg take would occur to prevent colony expansion on the island, along with land- and boat-based hazing and efforts to prevent double-crested cormorants from relocating in the Columbia River estuary.

Development and implementation of a management plan is a requirement under the Corps’ Endangered Species Act consultation with the National Marine Fisheries Service of the National Oceanic and Atmospheric Administration for the operation of the hydropower dams that make up the Federal Columbia River Power System.

Double-crested cormorants are protected under the Migratory Bird Treaty Act and are native to the Columbia River estuary.

Over the past decade, a large colony nesting on East Sand Island near the mouth of the Columbia River has consumed approximately 11 million juvenile salmonids per year. In recent years (2011-2013) consumption has averaged 18.5 million per year, according to the Corps.

East Sand’s double-crested cormorant colony has grown to about 14,900 nesting pairs in 2013, according to the Corps. That represents more than 40 percent of the species “western” population and is the single largest such colony on the West Coast. It is also likely the largest colony in North America.

The Corps is the lead agency in developing the EIS under the National Environmental Policy Act. The U.S. Fish and Wildlife Service, U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, Oregon Department of Fish and Wildlife and Washington Department of Fish and Wildlife are cooperating agencies to the EIS

As a part of long term management, once the target colony size is attained, the Corps is proposing to modify the terrain of East Sand Island to inundate nesting habitat for double-crested cormorants. This would occur by excavating sand on the western portion of the island and placing rock armor along the northern shore to ensure stabilization of the island.

The Corps will host an additional public webinar/conference during the comment period extension.

Questions or written comments on the draft EIS should refer to public notice CENWP-PM-E-14-08. Written comments are welcome through email, traditional mail or at the open houses. The Corps will categorize, summarize, respond to and consider comments to inform the decision-making process.